This proposal seeks support for the thirty-seventh in an annual series of meetings on Retroviruses to be held at Cold Spring Harbor Laboratory that has emerged as the premiere conference for this field. The proposed meeting will assemble leaders in the field, junior faculty, postdoctoral fellows and graduate students to discuss new, cutting-edge developments in the field of retrovirus biology. The meeting series is focused on the viruses and their interactions with host cells rather than the particular diseases they cause. The large majority of the work to be presented will be unpublished and subject to immediate comment and discussion by the audience. The 2012 meeting will be structured in a manner that parallels the biology of the viruses; beginning with the entry phase of the replication cycle, proceeding with post-entry events, including reverse transcription and integration, RNA-related events (transcription, processing, export, and packaging), particle assembly and release, pathogenesis/host factors, and concluding with antivirals and evolution. Selected speakers will include graduate students, postdoctoral fellows and junior faculty. Each session will be chaired by two leading scientists in the field selected by the organizers from among the registrants. Two eminent invited speakers will give special lectures to inspire and inform young scientists and to stimulate discussion between scientists working on related but distinct areas. There will also be three poster sessions where a majority of participants can present their work. The meeting will be of moderate size, and we expect ~450 retrovirologists in attendance.